\expandafter immediately after \tatechuyoko

[minamotorin]

When I was writing a macro, I realized that the following code causes ! Argument of \@secondoftwo has an extra }. with latest jlreq (4b760c7).

% This program is in the public domain.
\documentclass[tate]{jlreq}
\begin{document}
\tatechuyoko{A}\expandafter BC
\end{document}

I don't know if it's correct and why the following patch solves the issue, but the patch works.

# This patch is in the public domain.
diff --git a/jlreq.cls b/jlreq.cls
index 9a7d5b1..bc4adb5 100644
--- a/jlreq.cls
+++ b/jlreq.cls
@@ -500,7 +500,7 @@

 % #1の先頭が文字か
 \long\def\jlreq@ifletter#1{%
-  \jlreq@iffirsttoken{#1}{ }{\@secondoftwo}{%
+  \jlreq@iffirsttoken{#1}{~}{\@secondoftwo}{%
     \expandafter\expandafter\expandafter\jlreq@helper@ifletter\jlreq@getfirsttoken#1\jlreq@uniqtoken{}\jlreq@endmark@
   }%
 }

This error doesn't occur in jlreq up to a4c1608.

Category code of ` where\jlreq@ifletteris defined changed in a commit 4628414, the commit after a4c1608, because of scope of expl3 syntax. However, in\jlreq@ifletterwas not replaced by~`.

Thanks.

[abenori]

Thanks! You are completely right. I used your correction. c903cce

[minamotorin]

I confirmed c903cce. Thanks!

By the way, as I expected from the time I read the code of \tatechuyoko, sometimes putting control sequence after\tatechuyoko may not be good.

% This program is in the public domain.
\documentclass[tate]{jlreq}
\usepackage{bxghost}
\begin{document}

\tatechuyoko{A}B

\tatechuyoko{A}\relax B

\jghostguarded{\tatechuyoko{A}}B

\end{document}

In the first, I realized that \jghostguarded of bxghost pakcage doesn't work with jlreq.

% This program is in the public domain.
\documentclass{jlreq}
%\documentclass{ltjsarticle}
\usepackage{bxghost}% 2020/01/31 v0.3.0
\begin{document}

AB

\jghostguarded{A}B

%\catcode`\　=12

aaaa　aaaa

aaaa□aaaa

\end{document}

• The result of compiling the above code with jlreq. ~(Same for pLaTeX and LuaLaTeX)~

  

• The result of compiling the above code with ltjsarticle.

  

The cause of this seems to be that \xkanjiskip is not inserted around 　 in jlreq and 　 doesn't work as Japanese ghost.

Do you have any idea to use Japanese ghost without changing behavior of 　?

[minamotorin]

In LuaLaTeX, \xkanjiskip is inserted before 　. This is different from (u)pLaTeX.

% This program is in the public domain.
\documentclass{jlreq}
\begin{document}

aaaa\　□□

□□□\　aaa

aaaa　□□% <- This

aaaa□□□

□□□　aaa

□□□□aaa

\ifx\undefined\directlua\else
  \catcode`\　=12

  aaaa　□□

  aaaa□□□

  □□□　aaa

  □□□□aaa

\fi

\end{document}

• pLaTeX (same as upLaTeX)

  

• LuaLaTeX

  

[minamotorin]

Inserting of \xkanjiskip before 　 only happens when using jfm-jlreq.lua of 3a7010fbd8e07 or later. I have no idea what is wrong.

[abenori]

I added kanjiskip_natural = 1 to jfm-jlreq.lua which means that kanjiskip added to the glue between characters between 　 and alchar (here, alchar means non-Japanese character). But xkanjiskip is inserted. I don't know this is expected or not.

I do not remember why I added kanjiskip_natural = 1 here. I'll look it again.

[abenori]

I added kanjiskip_natural = 1 to jfm-jlreq.lua which means that kanjiskip added to the glue between characters between 　 and alchar (here, alchar means non-Japanese character). But xkanjiskip is inserted. I don't know this is expected or not.

See https://osdn.net/projects/luatex-ja/ticket/43512

[minamotorin]

After updating luatexja to 20220103.0, inserting of xkanjiskip before 　 doesn't occur. Thanks!

About Japanese Ghost, I'll ask in wtsnjp/BXghost.